How we calculate avoided CO2e emissions
The figures on this page are estimates based on published life-cycle assessment data from ADEME. They are updated quarterly.
What the counter shows
The counter on our site shows the total greenhouse gas emissions, in kilograms of CO2 equivalent (CO2e), that our customers have collectively avoided by choosing a refurbished device instead of a new one. It covers smartphones, tablets, laptops and desktop computers sold by mResell since 2013.
This figure is an estimate based on published scientific data, not a direct measurement. Below we explain exactly how it is calculated, what it includes, and what it does not.
We count individual devices, not sales — so a device that was returned and sold again still counts a single time. (In practice, devices are de-duplicated using their unique serial numbers.)
This figure reflects devices sold directly through the mResell webshop since 2013. Sales through our partner marketplaces are not yet included.
These shares reflect each category's contribution to the total avoided emissions. Laptops are currently the largest share, followed by smartphones. A category's share depends on two factors: how many devices were sold and the avoided emissions per device. A laptop or desktop avoids roughly two to three times more CO2e per device than a smartphone or tablet, but sales volumes also differ between categories — so the shares should not be read as a ranking of either device size or sales volume.
The principle: avoided emissions
Most of a digital device's climate impact does not come from using it — it comes from manufacturing it. Extracting raw materials, producing components and assembling the finished product account for the large majority of a device's lifetime greenhouse gas emissions. When you buy a refurbished device, no new device needs to be manufactured to serve your need. The emissions that would have been generated by that production are avoided.
We deliberately use the word “avoided” rather than “saved”. Buying a refurbished device does not remove emissions from the atmosphere; it prevents new emissions that would otherwise have occurred.
Our data source
Our calculation is based on the study Évaluation de l'impact environnemental d'un ensemble de produits reconditionnés (Assessment of the environmental impact of refurbished products), published in September 2022 by ADEME, the French Agency for Ecological Transition. It is a comprehensive independent life-cycle assessment of refurbished electronics, conducted in accordance with ISO 14040/14044 with an independent critical review, and based on primary data collected from refurbishers across the industry.
The study compares refurbished devices against new equivalents across their full life cycle — including the refurbishment process itself: replacement parts, logistics, testing, packaging and accessories. The avoided-emissions figures are therefore net figures: the footprint of refurbishing the device has already been subtracted.
Per-device avoided CO2e figures
The per-device figures shown in the impact element on our homepage are always expressed as emissions avoided compared to buying a new device of the same type. All four category figures come from a single source — ADEME (2022) — and are derived the same way.
These are ADEME category averages applied to the product types we sell — not measurements of the specific Apple models named.
- iPhone — on average 49.2 kg CO2e avoided, compared to buying new. Smartphone category factor, ADEME 2022.
- iPad — on average 40.6 kg CO2e avoided, compared to buying new. Tablet category factor, ADEME 2022.
- MacBook — on average 81.9 kg CO2e avoided, compared to buying new. Laptop category factor, ADEME 2022.
- iMac — on average 127.5 kg CO2e avoided, compared to buying new. Desktop category factor, ADEME 2022.
Figures are rounded at display time only; no rounding is applied to the stored values. Where a device type has no verified figure — for example watches, headphones and monitors — no claim is made and no slide is shown.
The calculation
The figures use ADEME's substitution approach with each category's ADEME reference second-life duration: two years for smartphones and tablets, three years for laptops and desktops. Avoided CO2e per device = ADEME's published per-year avoided figure multiplied by that reference second-life.
| Category | Avoided CO2e per device (kg) | Per-year figure (kg) | Reference second-life (yr) | Source |
|---|---|---|---|---|
| Smartphone | 49.2 | 24.6 | 2 | ADEME 2022 |
| Tablet | 40.6 | 20.3 | 2 | ADEME 2022 |
| Laptop | 81.9 | 27.3 | 3 | ADEME 2022 |
| Desktop | 127.5 | 42.5 | 3 | ADEME 2022 |
For a single device, the calculation is simply the per-year factor multiplied by the reference second-life — for example, one refurbished laptop: 27.3 kg/year × 3 years = 81.9 kg CO2e avoided.
These are ADEME's reference second-life durations, not measurements of our own customers' usage. ADEME notes that actual usage varies and that longer use increases the benefit.
The substitution assumption. Each figure assumes that a refurbished purchase replaces the purchase of a new device. This is the standard substitution assumption used in life-cycle assessment. The result is a comparison against buying new — it is not a removal of emissions from the atmosphere, and it is not an offset. No device is made “climate neutral”.
Total avoided CO2e = counted devices per category × the per-device factor above, summed across categories. Device counts come from our internal records and are not published for commercial reasons; the category shares of the total are shown above.
Key assumptions and limitations
Category averages, not per-model figures
The ADEME figures represent an average device in each category (for example, an average smartphone based on the French market). Individual models differ: a large laptop has a bigger manufacturing footprint than a small one. We use the category averages consistently for all models, which keeps the estimate conservative and transparent rather than precise per model.
Lifetime assumptions matter
The figures use ADEME's reference second-life durations: two years for smartphones and tablets, three years for laptops and desktops. ADEME notes that actual usage varies and that longer use increases the benefit.
Full substitution is assumed
The reference approach assumes each refurbished purchase fully replaces a new-device purchase. In reality, some refurbished purchases may not have displaced a new purchase one-for-one. This is the standard assumption in the industry and in the ADEME reference methodology, but it means the counter should be read as an estimate of avoided impact under that assumption.
Geography
The ADEME study models the French market and electricity mix. Manufacturing emissions — the dominant component — occur in the global supply chain and are broadly comparable for devices sold in Sweden and the rest of Europe, but logistics and use-phase details differ somewhat from our market.
What is excluded
Products for which no ADEME category factor exists — such as smartwatches, headphones, streaming boxes and monitors — are excluded from the counter entirely, even though refurbishing them also avoids emissions. The counter therefore understates our total impact rather than overstating it.
Equivalences
To make the figures easier to grasp, ADEME also expresses avoided emissions as car-driving equivalents: avoiding one year of a refurbished smartphone's emissions is equivalent to roughly 74 km of car travel, and one year of a refurbished desktop computer to roughly 127 km (ADEME 2022). This conversion is approximate and illustrative. We also report avoided raw material extraction, based on ADEME's MIPS (Material Input Per Service unit) figures per category: 76.9 kg/year (smartphone), 80.1 kg/year (tablet), 126.7 kg/year (laptop), 259.3 kg/year (desktop), multiplied by the same reference second-life durations as the CO2e figures.
Sources
- ADEME (2022). Évaluation de l'impact environnemental d'un ensemble de produits reconditionnés — Synthèse, September 2022. Fangeat, E. et al. Available at librairie.ademe.fr.
Questions about our methodology? Contact us at contact@mresell.co.uk.
